Edge ring for a thermal processing chamber

ABSTRACT

Embodiments of the present invention provide an edge ring for supporting a substrate with increased temperature uniformity. More particularly, embodiments of the present invention provide an edge ring having one or more fins formed on an energy receiving surface of the edge ring. The fins may have at least one sloped side relative to a main body of the edge ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Application Ser. No.61/446,026, filed Feb. 23, 2011, which is incorporated herein byreference.

BACKGROUND

1. Field

Embodiment of the present invention generally relates to a method andapparatus for fabricating devices on a substrate. More particularly,embodiments of the present invention provide a substrate supporting ringto support a substrate around the edge region in a processing chamber.

2. Description of the Related Art

In the processing of substrates, such as semiconducting wafers anddisplay panels, a substrate is placed on a support in a process chamberwhile suitable processing conditions are maintained in the processchamber. For example, a substrate can be heated in a controlled heatingcycle to be thermally processed. During a thermal process, a substratemay be supported by a supporting structure, such as an edge ring, aroundthe edge region while radiant energy source disposed above or below thesubstrate projects thermal energy towards the substrate.

FIG. 1A schematically illustrates a sectional view of a traditional edgering 101 used in a thermal processing chamber. The edge ring 101 has aninner diameter slightly smaller than an outer diameter of a substrate102 being processed. During processing, the substrate 102 is disposed ona supporting surface 105 of the edge ring 101 so that the edge ring 101contacts and supports the substrate 102 by an outer edge region 104.Thermal energy 103 may be directed to the substrate 102 below thesubstrate 102 and the edge ring 101 to heat the substrate 102.

However, the traditional edge ring 101 as shown in FIG. 1A sometimescause the temperature non-uniformity around the outer edge region 104 onthe substrate 102. The temperature non-uniformity becomes morepronounced when the substrate 102 is heated at a rapid rate. FIG. 1Bschematically illustrates temperature variations around the outer edgeregion 104 of a substrate during heating. In FIG. 1B, the x-axisindicates azimuthally locations in an outer edge of a substrate denotedby 0 to 360 degrees. The y-axis indicates a temperature variation froman average temperature in Celsius degrees. Each curve 110, 111represents a measurement of a substrate during rapid heating. As shownin FIG. 1B, the temperature variation around the edge region of asubstrate can be up to 8 degrees Celsius.

Therefore, there is a need for an improved substrate support forsupporting a substrate around the edge region in a processing chamber.

SUMMARY

Embodiments of the present invention generally provide apparatus andmethods for processing a substrate. More particularly, embodiments ofthe present invention provide an edge ring for supporting a substrate ina processing chamber.

One embodiment of the present invention provides an edge ring forsupporting a substrate in a processing chamber. The edge ring includes aring shaped body defined by an inner edge, an outer edge, an upper sideand a lower side, wherein the inner edge and outer edge are concentricabout a central axis. The edge ring also includes a lip extendingradially inward from the inner edge of the ring shaped body. At least aportion of an upper surface of the lip is configured to support asubstrate around an outer edge of the substrate so that the substrate issubstantially parallel to a major plane that is perpendicular to thecentral axis. The edge ring also includes a fin formed on at least oneof the upper side or lower side of the ring shaped body, wherein the finhas at least one sloped side relative to the ring shaped body.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1A is a schematic sectional view of a traditional edge ring.

FIG. 1B illustrates temperature variation on a substrate during heatingwhen supported by a traditional edge ring.

FIG. 2A is a sectional view of an edge ring according to one embodimentof the present invention.

FIG. 2B is a partial sectional perspective view of the edge ring of FIG.2A.

FIG. 2C is a partial sectional perspective view showing a bottom side ofthe edge ring of FIG. 2A.

FIG. 2D is a top view of the edge ring of FIG. 2A.

FIG. 2E is a bottom view of the edge ring of FIG. 2A.

FIGS. 3A-3G schematically illustrate edge rings according to embodimentsof the present invention.

FIGS. 4A-4D schematically illustrate edge rings for having an upperenergy receiving surface according to embodiments of the presentinvention.

FIG. 5 is a schematic sectional view of a processing chamber accordingto one embodiment of the present invention.

FIG. 6 includes plots showing performance comparison between traditionaledge ring and edge rings according to embodiments of the presentinvention.

FIGS. 7A-7C schematically illustrate edge rings according embodiments ofthe present invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation

DETAILED DESCRIPTION

Embodiments of the present invention provide apparatus and methods forfabricating devices on a substrate. More particularly, embodiments ofthe present invention provide an edge ring for supporting a substrateduring thermal processing with improved temperature uniformity.

Embodiments of the present invention provide an edge ring for supportinga substrate with increased temperature uniformity. More particularly,embodiments of the present invention provide an edge ring having one ormore surface area increasing structures formed on an energy receivingsurface of the edge ring. The surface area increasing structureincreases the ratio of exposed surface area and mass in the edge ring,thus, reducing radial temperature gradient during heating. The surfacearea increasing structures may include a fin extending vertically from aplanar ring body. According to one embodiment of the present invention,the fin may have at least one sloped side. The added mass of the surfacearea increasing structure also improves azimuthal thermal conductivityof the edge ring. Therefore, the edge ring according to embodiments ofthe present invention reduces azimuthal and radial deformation of theedge ring and improve uniformity of thermal exchange between the edgering and the substrate, thus improves processing uniformity.

Embodiments of the present invention also provide an edge having achamber contacting surface located on a plane close to a plane includingthe center of gravity of the edge ring. But positioning the chambercontacting surface at a level close to the center of gravity, the edgering is supported at a level close to the center of gravity, thusreducing and controlling the deformation of the edge ring duringprocessing.

FIG. 2A is a sectional view of an edge ring 200 according to oneembodiment of the present invention. The edge ring 200 is configured tosupport a substrate 202 during processing in a chamber. Generally, theedge ring 200 is disposed on a chamber component, such as a ring support201, and is configured to contact the substrate 202 by an edge region204 and allow the majority of the substrate 202 exposed to radiantenergy 206.

The edge ring 200 includes a ring shaped body 210. The ring shaped body210 is defined by an upper surface 212, a lower surface 214, an inneredge 216 and an outer edge 218. The inner edge 216 and the outer edge218 may be concentric circles about a central axis 232. The inner edge216 may have an inner radius 220 and the outer edge 218 has an outerradius 222. In one embodiment, the ring shaped body 210 may be planarand have a major plane 234 perpendicular to the central axis 232.

A lip 224 extends radially inward from the inner edge 216 of the ringshaped body 210. The lip 224 has an upper surface 226 configured tosupport the substrate 202 by the edge region 204. The lip 224 isconfigured to position the substrate 202 substantially parallel to themajor plane 234. The lip 224 forms a central opening 228 concentric tothe inner edge 216 with a radius 230 from the central axis 232. Thecentral opening 228 exposes the majority of a back surface 208 of thesubstrate 202 to the radiant energy 206.

In one embodiment, a fin 236 may be formed on the lower surface 214. Thefin 236 to reduce temperature gradient from the outer edge 218 to theinner edge 216 and the lip 224. The fin 236 increases the surface areaof the lower surface 214. In one embodiment, the fin 236 is a thin wallextending vertically from the lower surface 214.

In one embodiment, the fin 236 is a continuous circular wall concentricto the outer edge 218 and the inner edge 216, and the central opening228. The fin 236 may be positioned between the outer edge 218 and theinner edge 216. The fin 236 has a radius 238 from the central axis 232.The radius 238 of the fin 236 may be designed to achieve the radialtemperature gradient or temperature profile of the edge ring 200, thus,reduce deformation of the edge ring 200 during heating. In oneembodiment, the radial temperature gradient may be reduced bypositioning the fin 236 towards the inner edge 216.

Being continuous, the fin 236 also increases the stiffness of the edgering 200, and further reduces deformation along radial direction andalong azimuthal direction. Being continuous, the fin 236 also increasesazimuthal thermal conductivity of the edge ring 200, thus, improveuniformity and reduce deformation.

In one embodiment, the edge ring 200 includes a positioning rim 240extending from the ring shaped body 210 near the outer edge 218. Thepositioning rim 240 is configured to securely mount the edge ring 200 ona chamber component, such as a supporting ring 201 shown in doted linesin FIG. 2A.

In one embodiment, a bottom surface 242 of the positioning rim 240 isconfigured to contact the supporting ring 201 and receive support fromthe processing chamber. In one embodiment, the bottom surface 242 issubstantially planar and is positioned vertically in close proximity tothe center of gravity 244 of the edge ring 200. As shown in FIG. 2A, aplane 246 parallel to the major plane 234 passes the center of gravity244. The bottom surface 242, which receives supports from the chamber,is at a distance 248 from the plane 246. In one embodiment, the distance248 is about 0.75 mm or less. The bottom surface 242 may be above orbelow the center of gravity 244 for less than 0.75 mm.

According to embodiment of the present invention, by positioning theedge ring supporting surface vertically close to the center of gravity244, deformation of the edge ring, such as bucking. According to oneembodiment of the present invention, the direction of edge ring buckingcan be adjusted by supporting the edge ring 200 on a plane above orbelow the center of gravity 244.

In one embodiment, the edge ring 200 is configured to support thesubstrate 202 while the substrate 202 is exposed to radiant energy 206projected towards the backside 208 of the substrate 202. Both of theedge ring 200 and the substrate 202 are heated by the radiant energy206. The edge region 204 of the substrate 202 is shadowed from theradiant energy 206 by the lip 224 of the edge ring 200. The edge region204 is heated by direct thermal exchange with the lip 224 of the edgering 200.

The surface area increasing structure, such as the fin 236, increasesthe exposed surface of edge ring 200, thus, increasing thermalconductivity, reducing temperature gradient, and ultimately reducingdeformation in the edge ring 200. The position of the supporting surface242 which is close to the center of gravity 244, reduces bucking of theedge ring 200, thus also reduce deformation of the edge ring. Because ofthe reduced deformation of the edge ring 200, the lip 224 of the edgering 200 and the edge region 204 of the substrate 202 maintains soliddirect contact around the entire edge region 204, thus, achieves uniformheating in the edge region 204.

FIG. 2B is a partial sectional perspective view of the edge ring 200.FIG. 2C shows the edge ring 200 being supported by the supporting ring201 by the bottom surface 242 of the positioning rim 240. FIG. 2D is atop view of the edge ring 200. FIG. 2E is a bottom view of the edge ring200.

The edge ring 200 may be formed from a suitable material according tothe material of the substrate 202 being processed. For example, the edgering 200 may be formed from a material having a similar thermal capacityas the material of the substrate 202. For example, the edge ring 200 maybe formed from a silicon carbide material for processing a siliconsubstrate. The edge ring 200 may be formed by sintering a powdermaterial then machining to dimension. Details about the material andmethod for forming the edge ring can be found in U.S. Pat. Nos.6,888,104, 7,127,367, which are incorporated herein by reference.

Embodiments of the present invention provide an edge ring with surfacearea increasing structures formed on a surface that is configured toface a radiant energy source during a thermal processing. In oneembodiment, the ratio of edge ring surface area that is exposed to aradiant energy source and the mass of the edge ring may be above about0.55 meters squared per kilogram. In another embodiment, the ratio ofexposed area and the mass may be above about 0.70 meters squared perkilogram. In another embodiment, the ratio of exposed area and the massmay be between about 0.7 to about 1.0 meters squared per kilogram.

Various factors may be considered to improve or modify the edge ringaccording to process requirements. Exemplary factors include but notlimited to the ratio of exposed area and the mass of the edge ring, theouter diameter of the edge ring, the relative position of a supportingsurface to the center of gravity, thermal conductivity along the radialdirection, thermal conductivity along azimuthal direction, and stiffnessof the edge ring.

FIGS. 3A-3G are partial sectional views of edge rings according toembodiments of the present invention. The edge rings shown in FIGS.3A-3G are configured to support a substrate while the substrate beingheated from a radiant energy from disposed below the substrate and theedge ring.

FIG. 3A is a partial schematic sectional view of an edge ring 310 havinga surface area increasing fin 313 and configured for supporting asubstrate 302 while mounted on a supporting ring 301. The edge ring 310is similar to the edge ring 200 except the edge ring 310 is supported bya bottom surface 312 of a ring shaped body 311.

FIG. 3B is a partial schematic sectional view of an edge ring 310. Theedge ring 320 is similar to the edge ring 200 except the edge ring 320includes a fin 323 positioned at an inner edge 322 of a ring shaped body321. A lip 324 for supporting the substrate extends from the fin 323.

FIG. 3C is a partial schematic sectional view of an edge ring 330. Theedge ring 330 is similar to the edge ring 320 except the edge ring 330is supported by a bottom surface 332 of a ring shaped body 331.

FIG. 3D is a partial schematic sectional view of an edge ring 340. Theedge ring 340 having a fin 345 is similar to the edge ring 200 exceptthe edge ring 340 includes a lip 344 that is tilted at an angle 342 froma horizontal plane 341. In one embodiment, the angle is about 10degrees. In one embodiment, the location of supporting surface 343 maybe adjusted relative to the center of gravity so that the lip 344deforms to be substantially horizontal during processing.

FIG. 3E is a partial perspective view of an edge ring 350. The edge ring350 is similar to the edge ring 200 except the edge ring 350 a pluralityof discrete fins 351. The discrete fins 351 further increase the exposedsurface area.

FIG. 3F is a partial schematic sectional view of an edge ring 360. Theedge ring 360 is similar to the edge ring 200 except the edge ring 360includes two fins 361, 362 concentrically arranged. The two fins 361,362 further increases exposed surface area and stiffness of thestructure.

FIG. 3G is a partial schematic sectional view of an edge ring 370. Theedge ring 370 including a fin 375 is similar to the edge ring 200 exceptthe edge ring 370 includes a lip 371 having a raised portion 372. Theraised portion 372 has an upper surface 373 for contacting the substrate302. The raised portion 372 may be one continuous structure, or aplurality of discrete structures.

Even though, fins are illustrated in the above examples, surface areaincreasing structures may have any suitable form.

FIGS. 4A-4D schematically illustrate edge rings for having an upperenergy receiving surface according to embodiments of the presentinvention.

FIG. 4A shows an edge ring 410 having a fin 412 extending from an uppersurface 413 of a ring shaped body 411. The edge ring 410 is configuredfor supporting a substrate 402 while being heated by a radiant energysource 403 disposed above. The edge ring 410 includes a lip 414 forsupporting the substrate 402. In one embodiment, a plurality of pads 415is raised from the lip 414 for contacting the substrate 402.

FIG. 4B shows an edge ring 420 having an upwardly extending fin 422disposed near an inner edge 423 of a ring shaped body 421. A lip 424extends from the fin 422.

FIG. 4C shows an edge ring 430 having an upwardly extending fin 432 anda tilted lip 433.

FIG. 4D shows an edge ring 440 having an upper fin 441 and a lower fin442. The edge ring 440 is suitable when radiant sources are positionedboth above and below the substrate 402 and the edge ring 440.

FIG. 5 is a schematic sectional view of a processing chamber 500according to one embodiment of the present invention. The processingchamber 500 includes a chamber body 502 defining a processing volume504. A window 506 is formed on a bottom side of the chamber body 502.The window 506 may be formed form quartz. A radiant energy source 508 isdisposed below the window 506. The radiant energy source 508 isconfigured to direct radiant energy towards the processing volume 504.In one embodiment, the radiant energy source 508 includes a plurality oflamps. A reflection plate 510 is disposed on an upper wall 512 of thechamber body 502 inside the processing volume 504. A plurality ofsensors 526 may be disposed over the upper wall 512 to detecttemperatures in the processing volume 504 through sensor ports 524formed in the reflection plate 510 and the upper wall 512.

A raiser assembly 528 is configured to vertically move and rotate arotor 514 disposed in the processing volume 504. A supporting ring 516is disposed on the rotor 514.

An edge ring 518 is supported by the supporting ring 516. A substrate522 is supported by the edge ring 518 during processing. The edge ring518 and the substrate 522 are positioned above the radiant energy source508 so that the radiant energy source 508 can heat both the substrate522 and the edge ring 518. The edge ring 518 may be any edge ringsaccording to embodiments of the present invention. In one embodiment,the edge ring 518 includes a surface area increasing structure 520facing the radiant energy source 508.

During processing, the radiant energy source 508 is configured torapidly heat the substrate 522 positioned on the edge ring 518, whilethe edge ring 518 heats an edge region of the substrate 522 byconvection through direct contact. Edge rings according to embodimentsof the present invention improve temperature uniformity across thesubstrate 522, particularly along the edge regions shadowed by the edgering.

More detailed description of a thermal processing chamber may be foundin United State Patent Application Publication 2009/0298300, which isherein incorporated by reference.

Experiments have shown the embodiments of the present invention improvegreatly compared to traditional edge rings. FIG. 6 includes plotsshowing comparison between traditional edge ring and edge ringsaccording to embodiments of the present invention in term of edge ringdeformation.

Curve 601 shows deformation of a traditional edge ring as shown in FIG.1A while supporting a substrate being heated to 1090 degrees C.

Curve 602 shows deformation of the edge ring shown in FIG. 2A whilesupporting a substrate being heated to 1090 degrees C.

Curve 603 shows deformation of the edge ring shown in FIG. 3A whilesupporting a substrate being heated to 1090 degrees C.

Curve 604 and curve 605 show deformation of the edge ring shown in FIG.3C while supporting substrates being heated to 1090 degrees C.

FIG. 6 illustrates that edge rings according to embodiments of thepresent invention reduce edge ring deformation by about 80%.

Temperatures of the substrate being heated are also measured for theprocesses reflected in FIG. 6.

For the traditional edge ring shown in FIG. 1A, the typical standarddeviation of the temperature over the entire substrate is 16.22° C.while the substrate is heated to a target temperature of 1090° C.

For the edge ring shown in FIG. 2A, the typical standard deviation ofthe temperature over the entire substrate is 5.57° C. while thesubstrate is heated to a target temperature of 1090° C.

For the edge ring shown in FIG. 3A, the typical standard deviation ofthe temperature over the entire substrate is 3.60° C. while thesubstrate is heated to a target temperature of 1090° C.

For the edge ring shown in FIG. 3C, the typical standard deviation ofthe temperature over the entire substrate is 4.93° C. while thesubstrate is heated to a target temperature of 1090° C.

Therefore, embodiments of the present invention greatly increasetemperature uniformity during a thermal process.

FIGS. 7A-7C are partial sectional views of edge rings according toembodiments of the present invention. The edge rings shown in FIGS.7A-7C are similar to the edge ring 200 of FIGS. 2A-2E except having asurface increasing structure with one or more sloped surfaces.

FIG. 7A is a partial sectional view of an edge ring 700 according to oneembodiment of the present invention. The edge ring 700 includes asubstantially planar ring shaped body 702. The ring shaped body 702 hasa lip 714 extending radially inward for supporting a substrate 701thereon. A surface increasing structure, fin 704, extends from a lowersurface 702 a of the planar ring shaped body 702. The fin 704 reduces aradial temperature gradient in the edge ring 700 during heating byincreasing the ratio of exposed surface area and mass in the edge ring700. The fin 704 also increases stiffness of the edge ring 700. As shownin FIG. 7A, the fin 704 has an inner side 706 substantiallyperpendicular to the planar ring shaped body 702 and an outer side 708that is sloped relative to the planar ring shaped body 702.

Compared to fins with two vertical sides, such as the fin 236 of edgering 200, the sloped side 708 allows the similar effect with reducedtotal height. As shown in FIG. 7A, a total height 710 with the slopedfin 704 is shorter than a total height 712 with a vertical fin toachieve the same mass and the same stiffness. The reduced height canreduce the amount of raw material needed to manufacture the edge ring,therefore, reducing cost. For example, the edge rings are typicallymachined from an ingot segment. By reducing the total height of the edgering, the length of the ingot segment also reduces, thus, reduce theamount of raw material needed. Additionally, fins with sloped side canbe easier to manufacture than fins with straight sides, thus, furtherreducing costs.

FIG. 7B is a partial sectional view of an edge ring 720 according toanother embodiment of the present invention. The edge ring 720 issimilar to the edge ring 700 except that the edge ring 720 has a fin 724with a sloped inner side 726 and a vertical outer side 728 extendingfrom a planar ring shaped body 722.

FIG. 7C is a partial sectional view of an edge ring 740 according toanother embodiment of the present invention. The edge ring 740 issimilar to the edge ring 700 except that the edge ring 740 has a fin 744with a sloped inner side 746 and a sloped outer side 748 extending froma planar ring shaped body 742.

It should be noted that one or more sloped side may be combined with anyof the surface area increasing fins 236, 313, 323, 345, 351, 361, 362,375, 412, 422, 432, 441 described above.

Even though circular edge rings are described above, embodiments of thepresent invention may be applied to edge rings of other shapes, such assquared, rectangular, oval, etc. for processing substrates of differentshapes.

Even though a thermal process and thermal processing chamber aredescribed above, embodiments of the present invention may be used to anyprocess and in any process chamber where a supporting structure or asubstrate is exposed to a radiant energy.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. An edge ring for supporting a substrate in aprocessing chamber, comprising: a ring shaped body defined by an inneredge, an outer edge, an upper side and a lower side, wherein the inneredge and outer edge are concentric about a central axis; a lip extendingradially inward from the inner edge of the ring shaped body, wherein atleast a portion of an upper surface of the lip is configured to supporta substrate around an outer edge of the substrate so that the substrateis substantially parallel to a major plane that is perpendicular to thecentral axis; a positioning rim extending from the ring shaped body nearthe outer edge; and a fin formed between the lip and the positioning rimon at least one of the upper side or lower side of the ring shaped body,wherein the fin has at least one sloped side relative to the ring shapedbody.
 2. The edge ring of claim 1, wherein the fin extends from thelower side of the ring shaped body.
 3. The edge ring of claim 2, whereinthe fin forms a circular wall concentric to the inner edge and the outeredge, and the fin is positioned between the inner edge and the outeredge.
 4. The edge ring of claim 3, wherein the upper surface of the lipis below an upper surface of the ring shaped body so that the lip andbody form a recess for holding the substrate.
 5. The edge ring of claim4, wherein the fin is disposed at the inner edge of the ring shapedbody, and the lip extends from the fin.
 6. The edge ring of claim 2,wherein the lip is tilted at an angle relative to the major plane. 7.The edge ring of claim 1, wherein the fin configured to face a radiantenergy source.
 8. The edge ring of claim 2, wherein the positioning ringextends from the lower side of the ring shaped body, and a bottomsurface of the positioning ring is located in close proximity to thecenter of gravity of the edge ring.
 9. The edge ring of claim 1, whereinthe fin is disposed at the inner edge of the ring shaped body, and thelip extends from the fin.
 10. A substrate support, comprising: a bodyforming a closed loop, wherein the body is equal in width around theclosed loop; a lip extending inward from the body, wherein the lip hasan upper surface configured to receive a substrate around an outer edgeof the substrate, and the body surrounds the substrate when thesubstrate is disposed on the lip; a positioning rim extending from thering shaped body near the outer edge; and a fin formed between the lipand the positioning rim on at least one of the upper side or lower sideof the body, wherein the fin has at least one sloped side relative tothe body.
 11. The substrate support of claim 10, wherein the body iscircular.
 12. The substrate support of claim 11, wherein the fin forms acircular wall concentric to an inner edge and an outer edge of the body.13. The substrate support of claim 12, wherein the fin is disposed atthe inner edge of the body, and the lip extends from the fin.
 14. Achamber for processing a substrate, comprising: a chamber body defininga processing volume, where the chamber body has a window formedtherethrough; a substrate support base disposed in the processingvolume; an energy source disposed outside the window to direct radiantenergy towards the processing volume through the window; and an edgering disposed on the substrate support base for supporting substratethereon, wherein the edge ring comprises one or more surface areaincreasing structure facing the energy source, and the edge ringcomprises: a ring shaped body defined by an inner edge, an outer edge,an upper side and a lower side, wherein the inner edge and outer edgeare concentric about a central axis; a lip extending radially inwardfrom the inner edge of the ring shaped body, wherein at least a portionof an upper surface of the lip is configured to support a substratearound an outer edge of the substrate so that the substrate issubstantially parallel to a major plane that is perpendicular to thecentral axis; and a fin formed on at least one of the upper side orlower side of the ring shaped body, wherein the fin has at least onesloped side relative to the ring shaped body, and the fin is disposed atthe inner edge of the ring shaped body, and the lip extends from thefin.
 15. The chamber of claim 14, wherein the window is formed on abottom of the chamber body, and the energy source is disposed below theedge ring.
 16. The chamber of claim 15, wherein the fin extends from thelower side of the ring shaped body.
 17. The chamber of claim 16, whereinthe fin forms a circular wall concentric to the inner edge and the outeredge, and the fin is positioned between the inner edge and the outeredge.
 18. The chamber of claim 17, wherein the upper surface of the lipis below an upper surface of the ring shaped body so that the lip andbody form a recess for holding the substrate.
 19. The chamber of claim14, wherein the lip is tilted at an angle relative to the major plane.20. A chamber for processing a substrate, comprising: a chamber bodydefining a processing volume, where the chamber body has a window formedtherethrough; a substrate support base disposed in the processingvolume; an energy source disposed outside the window to direct radiantenergy towards the processing volume through the window; and an edgering disposed on the substrate support base for supporting substratethereon, wherein the edge ring comprises one or more surface areaincreasing structure facing the energy source, the window is formed on abottom of the chamber body, and the energy source is disposed below theedge ring, and the edge ring comprises: a ring shaped body defined by aninner edge, an outer edge, an upper side and a lower side, wherein theinner edge and outer edge are concentric about a central axis; a lipextending radially inward from the inner edge of the ring shaped body,wherein at least a portion of an upper surface of the lip is configuredto support a substrate around an outer edge of the substrate so that thesubstrate is substantially parallel to a major plane that isperpendicular to the central axis, and the upper surface of the lip isbelow an upper surface of the ring shaped body so that the lip and bodyform a recess for holding the substrate; and a fin formed on the lowerside of the ring shaped body, wherein the fin has at least one slopedside relative to the ring shaped body, the fin forms a circular wallconcentric to the inner edge and the outer edge, and the fin ispositioned between the inner edge and the outer edge, and the fin isdisposed at the inner edge of the ring shaped body, and the lip extendsfrom the fin.